Isobar may refer to:

• Isobar (meteorology), a line connecting points of equal atmospheric pressure reduced to sea level on the maps.
• Isobaric process, a process taking place at constant pressure
• Isobar (nuclide), one of multiple nuclides with the same mass but with different numbers of protons (or, equivalently, different numbers of neutrons).

• Isosurface
• All pages with titles containing isobar
• All pages with titles containing isobaric